This invention relates to an electroplating apparatus and, in particular, such an electroplating apparatus which comprises means for facilitating mixing and dissolution of a solute in a solvent, and minimising the amount of undissolved solutes to be carried away from a mixing chamber, e.g. into a chamber of the apparatus where electroplating takes place.
Prior electroplating apparatus is known. An example of prior electroplating apparatus consists of two housings wherein a respective chamber is located therein. A first chamber is for dissolving solutes in a solvent to form an electrolyte solution. The solution is then delivered to a second chamber in which electroplating occurs.
One problem associated with this conventional type of apparatus is that undissolved solute in the first chamber may be delivered, together with the electrolyte solution, to the second chamber. This not only contaminates the second chamber with undissolved solute, which will affect the electroplating process, it is also uneconomical as additional solute is needed to compensate the undissolved solute which is unused for the intended purpose in the second chamber.
Another problem associated with a conventional type of apparatus is that a simple stirring mechanism in the shape of a turbine arranged in a lower portion of the first chamber is often used. This design has a disadvantage in that an undesirably rough current is produced during the dissolution of the solute. Undissolved solute may undesirably be brought to an upper portion of the first chamber by the rough current and carried away from the first chamber.
The present invention seeks to provide an improved mixing apparatus as well as an improved electroplating apparatus which mitigates the disadvantages of the prior art apparatus while affording additional operating advantages.
According to a first aspect of the present invention, there is provided an apparatus useful for mixing comprising a chamber with at least one inlet allowing entry of a solute and a liquid solvent, at least one outlet allowing exit of a solution of the solute and solvent, and at least a separator having at least one generally upwardly facing surface and one generally downward facing surface, wherein the at least one generally upwardly facing surface and the at least one generally downwardly facing surface form at least part of a passageway allowing said solution to pass through and out of the chamber, and wherein undissolved solute is descendable along the generally upwardly facing surface.
Preferably, the separator may include a plurality of separating members.
Advantageously, each of the separating members may comprise a plate member.
Suitably, each plate member may provide a generally upwardly facing surface and a generally downwardly facing surface.
Preferably, the plate members may be disposed side by side with each other.
Advantageously, the upwardly facing surface and downwardly facing surface may be substantially parallel to each other.
Suitably, the upwardly facing surface and the downwardly facing surface may be slanted at substantially 55-65xc2x0 from a horizontal axis of the chamber.
Preferably, the upwardly facing surface and the downwardly facing surface may be slanted at substantially 60xc2x0 from the horizontal axis of the chamber.
Advantageously, the mixing apparatus may further comprise a device for agitating the solvent with the solute in said chamber.
Suitably, the mixing apparatus may further comprise a device for detecting concentration of the solution, wherein the detecting device may be located below the separator.
Preferably, the mixing apparatus may further comprise at least one device for allowing the solute to reach a lower portion of the chamber before being mixed with and dissolved in the solvent.
According to a second aspect of the present invention, there is provided an apparatus as described above, wherein said apparatus is part of an electroplating apparatus.
According to a third aspect of the present invention, there is provided an apparatus as described above, wherein said apparatus is liquidly connected to a least one plating cell.